Air borne gyrocompass



Oca?, 1941.

Filed April 26, 1940 F. D. BRADDON `AIR BORNE GYROCOMPASS III' 4 sheets-Sheet 1 INVENTOR ocr. 7, 1941. D. BADDON 2,257,730

V AIR BORNE GYROCOMPASS Filed April 26,` 1940 4 Sheets-Sheet 3 O Ct. 7, 1941. F D BRADDQN i 2,257,730

AIR BORNE GYROCOMPAS S Filed April 26, 1940 4 Sheets-Sheet 4l Patented Oct. 7, 1941` i 2,257,131 U i AmnonNE GrltoCoMPAss Ffoaorioxn. Brandon, Babylon', N. Y., wignor to SperryV Gyroscope Company, Inc., Brooklyn, N. Y., a corporation o! New York Application April 26.1940, serial No. 331,760

1o claims. (c1. ca -22s) kThis invention relates to air borne gyro com- One object small, simple and comparatively inexpensive direct readinggyro compass which is compact in form, silent in operation, and of non-magnetic construction so that it may be installed in the of the invention is to design n.

ships wheel house in full view of the helmsman and in proximity to the magnetic compass without disturbing the latter.

Another object of my invention is to simplify and improve the lconstruction of the air-borne type of gyro compass by employing a n ovel horizontal guide pivot between the rotor casing and the vertical ring, the pivot beingconnected to the vertical-ring by a iiexible diaphragm, thus making the bearing self-aligning. Preferably, such 'a bearing is employed at one side only of the casing, ypreferably the west side, so that the east side `may be employed to discharge the air used in spinning the rotor along the tilt axis thereof, thus minimizing possible disturbing torques from this. source. This air is preferably discharged within the vertical ring which encloses the rotor casing, theairfrom said ring being discharged upwardly, thereby minimizing any reactivetorques that might` otherwise be createdthereby.

A further improvement` accomplished by my invention is in the liquidigravitational control element. I propose to use as the liquid, a nonviscous or mobile organic compound of greater specific lgravity than oil but less than mercury, and I, propose to completely seal the same in glass containers to prevent evaporation `and contaminating, withadjustable means'to constrict the rate of ilowrtherebetween. f

Another improvement achievedbymy invention is leading the air supply in. throughthe shock mountingV iixtures,thus avoiding extra iiexible tubing, the position of which may vary and affect the balance of the compass. n Other objects of my invention willappearfrom the following description, from which it will be apparent .that many `features'thereof haveapplication to oiher types of 'gyroscopic instruments. 4-

W i Referring to the drawings, u 7 i V1'ig.f1`is a side elevation, partly in lsect-ion, of my improved airborne gyrocc'nnpass.' c 'Fig'. 2 is a yplan, "8.159 Partly insection; v .v Y

Fig'. 3 isa -vertical sectio'nthrough the'compass, looking north or south.

Fig. 4 is a vertical section of t e same, lookingeast or west. i

Fig. 5is a detail, partly in section, through the liquid gravitational element. 4 y n Fig. 6 is a sectional detail taken vapproximatelyonline i--S oiFlg.3.

Fig. 'l is a similar sectional detail taken vapproximatelyA on line 'II--l of Fig'. El.y j

Fig. 8 is a horizontalsectio thr ugh the rotor and its casing.

My gyroscopic compass isshown as mounted in the usual venclosing,bowl-shaped stand I by means of a gimbal ring 2, which ,universally supports the intermediate ring 3, the gimbal being supported in the bowl I on major trunnions l-'l with the minor trunnions (not shown)V at right angles thereto. The compass is shock mounted or iiexibly supported from the ring 3 by means of a plurality of universal rubber couplings 5, 5 which suspend the ringfS which supports-the compassl housing 'I infa shock absorbing suspension from thering 3. i I u The gyroscope, besides'- being air supported. is also preferably air spun. The air for both purposes is supplied from a pump (not shown) through the supply pipe 8 which" leads into a chamberv 9, fromwhich the air passesqthrough hollow trunnion I into a segmental channel Ill in the gimbal ring. Thence, theair passesto annular channel II in ring 3 through one of .the hollow minor trunnions (not shown) i, and thence itfpasses downwardly through a centralv bore or tube I2 in one or more of the shock mountings 5 into the pipes I3 leading within the lower extension Il on the compasshousing 1. Thence the air passes through filters I5 and I6 to a chamber Il. l through apertures I8 in theV central vertical stem I9 extending downwardly from the .vertical ring- 20 oi the compass. Another portionnot `theair in chamberv Il passes Voutwardly between the spherical. shaped button 2l onthelower-end of the stem I9 and the complementary'cup 224cm the lower end ofV the housinmthus furnishing an air bearing betweenthese parts.- Another portion ofthe air forms an air film between,- the upper` cup 23 and the vconcentric spherical surface of button 24 formed in the vertical ring, `'I'he vertical .ring .is ,thus mounted on airV bearings for turning about a vertical axis only. i, .o

`'I'he rotor. casing isv preferablymade upof three. parts,` one Vbeing anequatorial channeled ring 65 which carries vthe rotor bearings 66 and 61 and the sides of which closely approach the sides of the rotor to reduce windage losses.

A portionof the air then passes may be mounted on the stem button and cup bearings Above and below the said ring are bolted a pair of large hollow, concentric spherical buttons 25 `and 25' which t in complementary spherical concavities 26 and 21 in the Vertical ring 29 giving. the casing three degrees of freedom.

In order to suppress angular movement of the casing-about all axes except the horizontal E-W axis, I have shown the casing 65 as provided with a spherical button 30 at one side only, from which projects a hollow stem 32. On said stem is secured an oppositely facing button 33, said buttons forming portions of each of two oppositelyiacing concave air bearings 34 and 35 supported bythe vertical ring 2li, thereby preventing movement of the rotor casing except about the common diameter of said buttons. The complementary portions of said bearings are provided by a pair of oppositely facing cup members 34 and 35, air being forcedbetween said button and cup members from pipes 36, 36 con-` nected to the interior of stem |9, which in turn leads air within the chamber 31 between the cups. This air passes through ports 38 to pass outwardly between the complementary button' and cup surfaces. The chamber 31 is` enclosed by a ring 49 whichsupports both cup members passes from the chamber 31 into the interior of the stem 32, and thence outwardly through one or more driving nozzles 43. Air is also supplied to the upper spherical bearing 21 from the cham- `ber 31. For" this purpose, a flexible pipe 61 is shown asy leading from `the chamber 31, connecting with the'bore'61 Aleading through the top 'of the vertical ring and into the chamber 28, whence the air passes downwardly through aperture 69 to flow between the spherical surfaces on cap 25 and cup 21. l

Preferably, I also mount the damping means on said hollow stem 32. -For damping the compass, I use an air supported pendulum 44 which by complementary 45 and 46 similar in construction, but smaller than the vhereinbefore and is connected to the vertical ring by means exerts a reactive torque on the gyroscope about its vertical axis, while that portion of thev air which is engaged or spoiled4 bythe knife edge is deflected up the chute or channel 49 and out at the top in a direction so as to exert no torque on the compass. Hence any relative tilt of the pendulum and gyroscope causes j unbalanced torque about the vertical axis to ,reduce the tilt and damp the compass. The damping rate may be eifectively varied by an adjustable throttle valve 55.

No bearing whatever is provided at the side of the casing opposite the stem 32, and advantage is taken of this fact by discharging all of the used air from the rotor spinning means through apertures 56 (Fig. 8) in a hollow cylindrical extension 51 secured to the gyro. casing 65. The air is then discharged through a ringshaped screen 58 so that torque on the gyroscope is avoided. 'I'hence the air passes upwardly into the interior of the vertical`ring and out the grill |58 at 'the top'so that the air passes slowly into the atmosphere without disturbing the gyroscope. i

A knob 59 may be provided on top of a frame |59 secured to rotor casing 65 which may be pushed in a general axial direction so as to exert a torque about the horizontal axis of the compass to quickly reset the compass in azimuth.

Gravitational control may be furnished by liquid container framework |69 (Fig. 5) secured to one end of the rotor casing. As shown, the liquid containers 62 and 62 are made of glass connected at top and bottom by small bore glass tubing 63 and 64, so that the system is entirely closed to the atmosphere. 4I prefer to employ as the liquid for the ballistic a heavy mobile liquid, such as a heavy organic compound, such as methylene iodide, which has a specific gravity between that of water ci. oil and mercury.

Preferably, also,-I provide an adjustable throttle valve 12 in tube 63 so that the rate of now described bearings 34, 35. The pendulum 44 is shown as depending from the cup structure 46, while the oppositely facing cooperating buttons `45 are secured to the stem or trunnion 32. 'I'he lower portion of thependulum preferably dips into a container 41 containing oil or other uid.

Said lcontainer is mounted to tilt with the ,gyro Y casing 25, being shown as secured to the lower part of the circular framework 69', which in turn is secured to the back of the button 33 mounted on stem 32. To secure eii'ective damping, blades or paddles 48 may be secured to the pendulum. Also mounted onthe cup member 48 from Vwhich the pendulum depends are oppositely directed tubes and 5|, from the ends of which air jets 52 are normally dischargedhorizontally in opposite directions. Said jets are normally bisected by baiiies or spoilers 53 and 53', which are shown as formed by bending inwardly knife edges on segmental covering 54 for channels 49 formedv by the circular channelled enclosure 69' whichis secured to button 35 on the gyroscope. Said enclosure hasa pair of apertures 6| n'ormally in line' with but of greater height' than .iets 52, permitting limited tilt of the jet. Enclosure 60' thus, acts to shield the pendulum from stray air currents. That Aportion of the air which is not engaged by the knife edges of the liquid may be varied at will to secure properv out-of-phase relation between the rate y of flow and the normal roll and pitch of the ship.

In order that my improved compass may be used in the wheel house without disturbing the magnetic compass, I preferably construct all parts of the compass, except possibly the ball bearings, of non-magnetic material, the metals employed being preferably aluminum r`alloy .for theisupporting structure and brass for the rotor 10. The rotor shaft 1'| may also be of brass, but is preferably made of the same material as the rotor bearing ring 65, i.l e., of aluminum alloy, to avoid troublesome temperature compensation.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be it is intended that all above description matter contained in the or shown yin the accompanying drawings shall be interpreted vas illustrative fand not in a limiting sense.

Having described'my liiyention, what I clim and desire to secure by Letters Patent is:

1. Inair spun gyrosccpic apparatus, a supporting ring for the gyroscope. a universal mounting for said hollow'pivots for ring and from said gimbal ringv to said inner ring, and rubbershock mountings for supporting said compass from said inner ring, at least one ring including a gimbal ring, leading air into said gimbal center o! the casing to side only' of said casing, and air bearings between said stem and said vertical ring permitting rotation ot said casing only about `au E-W- axis.

3. Inan air spun Igyroscopic apparatus. the combination with a gyro casing. a normally horisontal pivot means therefor at one side of said casing, means whereby the spinning air is introduced through said pivot, means whereby the used air is discharged in a plurality o! directions radially oi said horizontal pivot axis froml the opposite side otsaid casing, and means for directing the discharged air upwardly at the "tubes connecting said containers both at'the bottom and at the top, and an organic mobile liqavoid torques thereon uid sealed in said containers and tubes oi a speciiic gravity greater than water and lessthan mercury.

5. In an air spun gyroscopic compass, a generally shperical rotor casing, a vertical ring sub- `stantially surrounding said casing. air bearings` between said ring and casing whereby said casing is supported for oscillation about an E-W horisontal axis within said ring, means'for supwrting said ring for turning about a vertical axis. and means for discharging air from said casing within said ring along said E-W axis. said ver- A geni: ring having an openina at the top permitaxis 6.

l axis, comprising a stem extending E-W from one sidsonly oi said casing. a guide bearing betweensaidstemandsaidcasingpermittingrotation o! said 'casing about said E-W axis, and means for ilexihly supportinglthe fixed portion of said bearing is seit-aligning.

7. In an air borne gyro compass, a generally spherical rotor casing, a vertical ring. spherical air bearings universally supporting said casing within said ring, means for anchoring said casing to said ring about all axes except an E-W axis comprising a stem extending E-W from one side only of said casing, air bearings between said stem and said vertical ring permitting rotation of said casing only about an E--W axis, and means for iiexibly supporting the portion of said bearings secured to said vertical ring from the vertical ring, whereby said bearings are seli- 8. In a gyro compass, a rotor and rotor bearin'g casing, a vertical ring, bearings universally supporting said casing within said ring for anchoring said casing iosaid ring about all axes except an E-W axis, comprising a stem extending E-W from one side only ot said casing, a guide bearing between said stem and said casing permitting rotation 'of said casing about said 1li-W axis, a pendulum also pivoted on said stem, and means controlled by the relative tilt of said pendulum and casing for damping the compass.

9. ,In an air borne gyro compass, a generally spherical rotor casing, a vertical ring. spherical air bearings universally supporting said casing within said ring, meansior anchoring said casing to said ring about all axes except an E-W axis comprising a stem extending E-W from one side only of said casing, air bearings between said stem and said vertical ring permitting rotation of said casing only about an E-W axis, a pendulum, air bearings supporting said pendulum on said stem, and air ilow means controlled by relative tilt of said pendulum and casing tor I damping the compass.

l0. In an air borne gyro compass. a generally spherical rotor casing, a vertical ring. spherical fair bearings universally supporting said casing within said ring. means forv anchoring said casing to said ring about all axes except an E-W axis comprising a stem extending E-W from onesideonlyot saidcasing,andairbearingsbetween said stem and said vertical ring permitting rotation oi' said casing only about an E'-W axis, said casing having apertures therein on the side 50 thereof opposite said stem, permitting exhausting threairdi'rom said casing adjacent the axis opposi sai stem.

A l :mann-mcg n. BRDnoN.

in said ring, whereby the bearing 

